diff --git a/packages/hermes-inspector-msggen/__tests__/CommandTest.js b/packages/hermes-inspector-msggen/__tests__/command-test.js
similarity index 100%
rename from packages/hermes-inspector-msggen/__tests__/CommandTest.js
rename to packages/hermes-inspector-msggen/__tests__/command-test.js
diff --git a/packages/hermes-inspector-msggen/__tests__/EventTest.js b/packages/hermes-inspector-msggen/__tests__/event-test.js
similarity index 100%
rename from packages/hermes-inspector-msggen/__tests__/EventTest.js
rename to packages/hermes-inspector-msggen/__tests__/event-test.js
diff --git a/packages/hermes-inspector-msggen/__tests__/GraphTest.js b/packages/hermes-inspector-msggen/__tests__/graph-test.js
similarity index 84%
rename from packages/hermes-inspector-msggen/__tests__/GraphTest.js
rename to packages/hermes-inspector-msggen/__tests__/graph-test.js
index b890c050ea8905..5d4043b80e0017 100644
--- a/packages/hermes-inspector-msggen/__tests__/GraphTest.js
+++ b/packages/hermes-inspector-msggen/__tests__/graph-test.js
@@ -25,8 +25,8 @@ beforeEach(() => {
 
 // checks id1 occurs after id2 in arr
 function expectOccursAfter(arr, id1, id2) {
-  let idx1 = arr.indexOf(id1);
-  let idx2 = arr.indexOf(id2);
+  const idx1 = arr.indexOf(id1);
+  const idx2 = arr.indexOf(id2);
 
   expect(idx1).not.toBe(-1);
   expect(idx2).not.toBe(-1);
@@ -35,7 +35,9 @@ function expectOccursAfter(arr, id1, id2) {
 
 test('detects cycle', () => {
   graph.addEdge('C2', 'A1');
-  expect(() => graph.traverse(['A2'])).toThrow(/^Not a DAG/);
+
+  const {cycles} = graph.traverse(['A2']);
+  expect(cycles).toContainEqual({from: 'A1', to: 'B1'});
 });
 
 test('checks for presence of root', () => {
@@ -43,10 +45,10 @@ test('checks for presence of root', () => {
 });
 
 test('traverses partial graph', () => {
-  let ids = graph.traverse(['B1', 'A3']);
+  const {nodes: ids} = graph.traverse(['B1', 'A3']);
 
   // Check that expected nodes are there
-  let sortedIds = ids.slice().sort();
+  const sortedIds = ids.slice().sort();
   expect(sortedIds).toEqual(['A3', 'B1', 'B2', 'C1', 'C2', 'C3']);
 
   // Check that the result is topologically sorted
@@ -59,10 +61,10 @@ test('traverses partial graph', () => {
 });
 
 test('traverses complete graph', () => {
-  let ids = graph.traverse(['A1', 'A2', 'A3']);
+  const {nodes: ids} = graph.traverse(['A1', 'A2', 'A3']);
 
   // Check that expected nodes are there
-  let sortedIds = ids.slice().sort();
+  const sortedIds = ids.slice().sort();
   expect(sortedIds).toEqual(['A1', 'A2', 'A3', 'B1', 'B2', 'C1', 'C2', 'C3']);
 
   // Check that the result is topologically sorted
diff --git a/packages/hermes-inspector-msggen/__tests__/HeaderWriterTest.js b/packages/hermes-inspector-msggen/__tests__/header-writer-test.js
similarity index 95%
rename from packages/hermes-inspector-msggen/__tests__/HeaderWriterTest.js
rename to packages/hermes-inspector-msggen/__tests__/header-writer-test.js
index da8bf0c03a6b50..5ba2bb2a1158b5 100644
--- a/packages/hermes-inspector-msggen/__tests__/HeaderWriterTest.js
+++ b/packages/hermes-inspector-msggen/__tests__/header-writer-test.js
@@ -40,8 +40,12 @@ test('emits type decl', () => {
   expectCodeIsEqual(stream.get(), `
     struct debugger::Location : public Serializable {
       Location() = default;
+      Location(Location&&) = default;
+      Location(const Location&) = delete;
       explicit Location(const folly::dynamic &obj);
       folly::dynamic toDynamic() const override;
+      Location& operator=(const Location&) = delete;
+      Location& operator=(Location&&) = default;
 
       runtime::ScriptId scriptId{};
       int lineNumber{};
diff --git a/packages/hermes-inspector-msggen/__tests__/ImplementationWriterTest.js b/packages/hermes-inspector-msggen/__tests__/implementation-writer-test.js
similarity index 100%
rename from packages/hermes-inspector-msggen/__tests__/ImplementationWriterTest.js
rename to packages/hermes-inspector-msggen/__tests__/implementation-writer-test.js
diff --git a/packages/hermes-inspector-msggen/__tests__/PropertyTest.js b/packages/hermes-inspector-msggen/__tests__/property-test.js
similarity index 100%
rename from packages/hermes-inspector-msggen/__tests__/PropertyTest.js
rename to packages/hermes-inspector-msggen/__tests__/property-test.js
diff --git a/packages/hermes-inspector-msggen/__tests__/TypeTest.js b/packages/hermes-inspector-msggen/__tests__/type-test.js
similarity index 100%
rename from packages/hermes-inspector-msggen/__tests__/TypeTest.js
rename to packages/hermes-inspector-msggen/__tests__/type-test.js